package org.mobicents.ss7;

import java.io.InputStream;
import java.util.Collections;
import java.util.Map;
import java.util.Properties;

/**
 * 
 * @author amit bhayani
 *
 */
public final class Version {

   /**
	 * The single instance.
	 */
	public final static Version instance = new Version();

	/**
	 * The version properties.
	 */
	private Properties props;	
	
	/**
	 * Do not allow direct public construction.
	 */
	private Version() {		
		props = loadProperties();
	}

	/**
	 * Returns an unmodifiable map of version properties.
	 *
	 * @return 
	 */
	public Map getProperties() {
		return Collections.unmodifiableMap(props);
	}

	/**
	 * Returns the value for the given property name.
	 *
	 * @param name - The name of the property.
	 * @return The property value or null if the property is not set.
	 */
	public String getProperty(final String name) {
		return props.getProperty(name);
	}

	/**
	 * Returns the version information as a string.
	 *
	 * @return Basic information as a string.
	 */
	public String toString() {		
		StringBuilder sb = new StringBuilder();
		boolean first = true;
		for (Object key : props.keySet()) {
			if (first) {
				first = false;
			} else {
				sb.append(" , ");
			}
			sb.append(key).append(" = ").append(props.get(key));
		}
		return sb.toString();		
	}

	/**
	 * Load the version properties from a resource.
	 */
	private Properties loadProperties() {

		props = new Properties();

		try {			
			InputStream in = Version.class
					.getResourceAsStream("version.properties");
			props.load(in);
			in.close();			
		} catch (Exception e) {
			throw new Error("Missing version.properties");
		}

		return props;
	}
	
}
